Engine/Transmission (1994 - 1998) Choking or spuddering?

[patrobertson]

My 96 runs well, but when I am in 1st or second and get ont he throttle when its cold it will cough and seems to get choked up likes it not burning all the fuel, some white smoke and than its fine. Its 5sp, 11#, (#10 waiting to be installed as soon as I can get bolt out, stripped) 60hp injectors, 3000gsk, 16cm housing, I put a . 020 over head gasket on few thousand miles ago, and the timing was at 15. 5 deg. I am assuming that being at 4500 ft, the thicker gasket and my timing may have slipped would cause the chamber pressure to drop enough to not burn effectivley or effeciently? Everything else is great, no problems anywhere and when it get warm its fine, just down low if you give it too much fuel. I am going to go to 18 deg of timing pretty soon and see if that clears it up. I do know that the motor noise has gotten alot quieter and shuts down without as much violent shaking since I did my last head gasket. (#2) Once again I appreciate all your help.



Shane

 

[MCummings]

Did you ever fix this?



I've got a customers truck, with only a removed AFC that does what you are saying, but it doesn't matter if it's hot or cold. Has good power, it only coughs/smokes(white) at very low boost, and light throttle.



Anybody have any comments on this ?



Thanks,

Merrick Cummings Jr



(maybe a bad Transfer Pump?)

 

[patrobertson]

I have not fixed it.

I was hoping bumping my timing would do it, but I have yet to get my timing done so I really don't know. I put in a gsk and #10, and a 16cm exhaust housing with no change. It has been warm here in Utah 90-100+ so I am a little worried if it gets cold what it will do. I am thinking in your case maybe the timing slipped? I have good power but I don't have the engine noise, so I think the head pressure is down too far, and won't ignite all the fuel, causing spuddering and choking but once boost comes up and egts are hot its fine.

Thats the only thing I can think of, but if I coast and hit the throttle real quick it will choke even if its warm so I am pretty sure its a head pressure / compression thing. Seem like it happened when I put in the larger injectors and headgasket about 10-15k ago which makes sense to me.



If anyone has some ideas please let us know, PLEASE



I appreciate it

Shane

 

[Howard Durand]

Have you made any changes to the AFC starwheel setting?

My 94 didn't want to accelerate after I installed the Banks system but after several experimental adjustments to the AFC, it got up and going nicely right from a standstill.

I think I finally settled on about 30 clicks of the starwheel toward the engine.

 

[HoleshotHolset]

Check the fuel pressure... .



Pre-screen/main fuel filter - are they clogged up?



Feed/return fuel lines - do they NOT leak? (... sometimes it's hard to tell until you replace them. )



Matt

 

[MCummings]

Originally posted by HoleshotHolset

Check the fuel pressure... .



Pre-screen/main fuel filter - are they clogged up?



Feed/return fuel lines - do they NOT leak? (... sometimes it's hard to tell until you replace them. )



Matt

Where is the pre-screen?



Just changed fuel filter.



I'm ordering the TsT fuel pressure test kit today. (adaptor bolt)

Overflow spring was about . 4" and had to shims about . 2". I stretched the overflow spring to ~. 550" and it didn't change a thing.



I'm guessing low fuel pressure also. That's the last thing it could be.



It's not the AFC, and it's not the plate.



Before I tore into the truck, the truck was VERY low on power (acted like a clogged/plugged AFC).



Just yesterday, his truck was a little hard to start (he has had low power for about 2 weeks, untill I slid the plate, and pulled the AFC arm)



His truck runs good, idles fine, has very good top-end. I'm guessing only low fuel pressure, but the return lines MAY be leaking since it was a little hard to start yesterday.



Justwaitingforanadaptor,

Merrick Cummings Jr

 

[HoleshotHolset]

Merrick:



You could have made your own adapter out of an old overflow valve... . just tap it for 1/8"-NPT and hook up a gauge. You could use a banjo bolt - but they don't have much 'meat' to them.....

I used an old overflow valve for my fuel pressure gauge - I even drilled out all the holes to match the OEM banjo bolt that I replaced.



The pre-screen is down by the lift pump/fuel heater - which chills out by the starter. Be prepared to get a diesel shower.....

I think dodgeram.org has some pictures/instructions... . but it's really straightforward.



I bought my pre-screen 'kit' from Cummins - it wasn't expensive at all.



Check them lines and replace 'em with the USCG rated stuff - it's a pain to clamp down since it is so beefy - but it will probably be the last time it would need to be replaced.



Matt

 

[patrobertson]

MCummings

Let me know what you find. My truck runs fine so I didn't even think to check fuel pressure. Question why would it spudder down low in the rpm say off idle and not up high where it uses more fuel or is my theory off. So check the pre screen down by the starter, I will try to find out where that is and see if it helps.

Thanks for the replies.



Shane